Ring-opened azlactone initiators for nitroxide-mediated polymerization

ABSTRACT

Initiators for nitroxide-mediated radical polymerizations are described. The initiators have an azlactone or ring-opened azlactone moiety to provide telechelic (co)polymers.

[0001] This application is a divisional of U.S. Ser. No. 10/358,767,filed Feb. 5, 2003, now allowed, the disclosure of which is hereinincorporated by reference.

FIELD OF THE INVENTION

[0002] The present invention provides initiators for nitroxide-mediatedradical polymerization (NMP) processes.

BACKGROUND

[0003] In conventional radical polymerization processes, thepolymerization terminates when reactive intermediates are destroyed orrendered inactive; radical generation is essentially irreversible. It isoften difficult to control the molecular weight and the polydispersity(molecular weight distribution) of polymers produced by conventionalradical polymerization, in order to achieve a highly uniform andwell-defined product. It is also often difficult to control radicalpolymerization processes with the degree of certainty necessary inspecialized applications, such as in the preparation of end functionalpolymers, block copolymers, star (co)polymers, and other noveltopologies.

[0004] In a controlled radical polymerization process radicals aregenerated reversibly, and irreversible chain transfer and chaintermination are absent. There are four major controlled radicalpolymerization methodologies: atom transfer radical polymerization(ATRP), reversible addition-fragmentation chain transfer (RAFT),nitroxide-mediated polymerization (NMP) and iniferters, each methodhaving advantages and disadvantages.

[0005] Nitroxide mediated radical polymerization (NMP) has beendescribed as a simple, versatile and efficient controlled radicalpolymerization process. See, e.g., C. J. Hawker et al., “New PolymerSynthesis by Nitroxide Mediated Living Radical Polymerizations”,Chemical Reviews, 2001, pp. 3661-3688. NMP processes employ an alkoxyamine as an initiator to produce a polymeric radical in the presence ofa monomer.

[0006] There is a need for a radical polymerization process whichprovides telechelic (co)polymers having a predictable molecular weightand a narrow molecular weight distribution (low “polydispersity”). Afurther need is for a radical polymerization process which issufficiently flexible to provide a wide variety of products, but whichcan be controlled to the degree necessary to provide highly uniformproducts with a controlled structure (i.e., controllable topology,composition, etc.). There is further need for a controlled radicalpolymerization process which provides telechelic (co)polymers capable ofentering into further polymerization or functionalization throughreactive end-groups, particularly electrophilic end groups.

SUMMARY OF THE INVENTION

[0007] In one aspect, the present invention provides initiators fornitroxide-mediated radical polymerization processes that comprisecompounds of the Formula I:

[0008] wherein X is H, an alkyl group, a cycloalkyl group, aheterocyclic group, an arenyl group, an aryl group, a cyano group, anacyl group or the residue of a free-radical initiator;

[0009] R¹ is H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group or an aryl group; ON(R²)₂ is the residue of anorganonitroxide;

[0010] R³ and R⁴ are independently selected from an alkyl, a cycloalkylgroup, an aryl group, an arenyl group, or R³ and R⁴ taken together withthe carbon to which they are attached form a carbocyclic ring;

[0011] Q is a linking group selected from a covalent bond, (—CH₂—)_(o),—CO—O—(CH₂)_(o)—, —CO—O—(CH₂CH₂O)_(n)—, —CO—NR⁶—(CH₂)_(o)—,—CO—S—(CH₂)_(o)—, where o is 1 to 12, and R⁶ is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup;

[0012] each n is 0 or 1;

[0013] q is 0 or 1; and

[0014] m is 0 to 20.

[0015] The present invention also provides initiators that comprise thering-opened reaction product of the initiators of Formula I and areactive compound, such as an aliphatic compound, having one or morenucleophilic groups. Such initiators have the general Formula II:

[0016] wherein

[0017] X is an H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group, an aryl group, a nitrile, an acyl group or theresidue of a free-radical initiator;

[0018] R¹ is H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group or an aryl group;

[0019] ON(R²)₂ is the residue of an organonitroxide;

[0020] R³ and R⁴ are each independently selected from an alkyl, acycloalkyl group, an aryl group, an arenyl group, or R³ and R⁴ takentogether with the carbon to which they are attached form a carbocyclicring;

[0021] Q is a linking group selected from a covalent bond, (—CH₂—)_(o),—CO—O—(CH₂)_(n)—, —CO—O—, —(CH₂CH₂O)_(n)—, —CO—NR⁶—(CH₂)_(o)—,—CO—S—(CH₂)_(n)—, where o is 1 to 12, and R⁶ is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup;

[0022] each n is 0 or 1;

[0023] q is 0 or 1;

[0024] m is 0 to 20;

[0025] Z is O, S or NR⁶, wherein R⁶ is H, an alkyl group, a cycloalkylgroup, an arenyl group, a heterocyclic group or an aryl group;

[0026] R⁵ is an organic or inorganic moiety and has a valency of p, R⁵is the residue of a mono- or polyfunctional compound of the formulaR⁵(ZH)_(p).

[0027] The initiators of the present invention provide (co)polymershaving a predictable molecular weight and a narrow molecular weightdistribution. Advantageously, the initiators provide novel multireactiveaddition polymers having first and second terminal reactive groups thatmay be used for further functionalization. The present invention furtherprovides a controlled radical polymerization process useful in thepreparation of terminal-functionalized (telechelic) (co)polymers, blockcopolymers, star (co)polymers, graft copolymers, and comb copolymers.The process provides these (co)polymers with controlled topologies andcompositions.

[0028] The control over molecular weight and functionality obtained inthis invention allows one to synthesize numerous materials with manynovel topologies for applications in coatings, surface modifications,elastomers, sealants, lubricants, pigments, personal care compositions,composites, inks, adhesives, water treatment materials, hydrogels,imaging materials, telechelic materials and the like.

[0029] In another aspect, the invention provides a method forpolymerization of one or more olefinically unsaturated monomerscomprising addition polymerizing one or more olefinically unsaturatedmonomers using the azlactone initiators of Formula I, or the ring-openedazlactone initiators of Formula II.

[0030] It is to be understood that the recitation of numerical ranges byendpoints includes all numbers and fractions subsumed within that range(e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0031] It is to be understood that all numbers and fractions thereof arepresumed to be modified by the term “about.”

[0032] It is to be understood that “a” as used herein includes both thesingular and plural.

[0033] The general definitions used herein have the following meaningswithin the scope of the present invention.

[0034] The term “alkyl” refers to straight or branched, cyclic oracyclic hydrocarbon radicals, such as methyl, ethyl, propyl, butyl,octyl, isopropyl, tert-butyl, sec-pentyl, cyclohexyl, and the like.Alkyl groups include, for example, 1 to 18 carbon atoms, preferably 1 to12 carbon atoms, or most preferably 1 to 6 carbon atoms.

[0035] The term “aryl” means the monovalent residue remaining afterremoval of one hydrogen atom from an aromatic compound which can consistof one ring or two fused rings having 6 to 12 carbon atoms.

[0036] The term “arenyl” means the monovalent residue remaining afterremoval of a hydrogen atom from the alkyl portion of a hydrocarboncontaining both alkyl and aryl groups having 6 to 26 atoms.

[0037] The term “azlactone” means 2-oxazolin-5-one groups and2-oxazolin-6-one groups of Formula I, where n is 0 and 1, respectively.

[0038] The term “heterocyclic group” or “heterocycle” means themonovalent residue remaining after removal of one hydrogen atom from ancycloaliphatic or aromatic compound having one ring or two fused ringshaving 5 to 12 ring atoms and 1 to 3 heteroatoms selected from S, N, andnonperoxidic O. Useful heterocycles include azlactonyl, pyrrolyl, furan,thiophenyl, imidazolyl, pyrazolyl, thiazolyl, oxazolyl, pyridinyl,piperazinyl, piperidinyl, hydrogenated and partially hydrogenatedderivatives thereof.

[0039] The term “multifunctional” means the presence of more than one ofthe same functional reactive group;

[0040] The term “multireactive” means the presence of two or more of twodifferent functional reactive groups;

[0041] The term “polyfunctional” is inclusive of multireactive andmultifunctional.

[0042] The term “molecular weight” means number average molecular weight(Mn), unless otherwise specified.

[0043] The term (co)polymer refers to homo- and copolymers.

[0044] The term (meth)acrylate refers to both methacrylate and acrylate.

DETAILED DESCRIPTION

[0045] The present invention provides novel initiators of Formula I andthe corresponding ring-opened initiators of Formula II for controlledradical polymerization processes.

[0046] wherein

[0047] X is an H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group, an aryl group, a nitrile, an acyl group or theresidue of a free-radical initiator;

[0048] R¹ is H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group or an aryl group;

[0049] ON(R²)₂ is the residue of an organonitroxide;

[0050] R³ and R⁴ are each independently selected from an alkyl, acycloalkyl group, an aryl group, an arenyl group, or R³ and R⁴ takentogether with the carbon to which they are attached form a carbocyclicring;

[0051] Q is a linking group selected from a covalent bond, (—CH₂—)_(o),—CO—O—(CH₂)_(n)—, —CO—O—, —(CH₂CH₂O)₀—, —CO—NR⁶—(CH₂)₀—,—CO—S—(CH₂)_(o)—, where o is 1 to 12, and R⁶ is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup;

[0052] each n is 0 or 1;

[0053] q is 0 or 1;

[0054] m is 0 to 20;

[0055] Z is O, S or NR⁶, wherein R⁶ is H, an alkyl group, a cycloalkylgroup, an arenyl group, a heterocyclic group or an aryl group;

[0056] R⁵ is an organic or inorganic moiety and has a valency of p, R⁵is the residue of a mono- or polyfunctional compound of the formulaR⁵(ZH)_(p).

[0057] The organonitroxide moiety, —ON(R²)₂, may comprise the residue ofany hindered organonitroxide which, on exposure to thermal energy,homolytically cleaves at the C-0 bond to form a radical. The hinderedorganonitroxide moieties are of the general formula:

[0058] wherein

[0059] R⁷ is an alkyl group, a cycloalkyl group, an arenyl group, aheterocyclic group, an aryl group,

[0060] R⁸, and R⁹ are independently H, or an alkyl group, a cycloalkylgroup, an arenyl group, a heterocyclic group, an aryl group,

[0061] R⁷ and R⁸, or R⁸ and R⁹, may be taken together to form acarbocyclic ring structure. Each of R⁷, R⁸, or R⁹ may be substituted byan alkoxy group, an aryloxy group, a silyl group, a boryl group, aphosphino group, an amino group, a thio group a seleno group, andcombinations thereof. Reference may be made to U.S. Pat. No. 6,472,486,incorporated herein by reference.

[0062] Useful organonitroxides include:

[0063] Initiators of Formula I may be prepared using the generalizedschemes as shown, where “Az” refers to the pendent azlactone moiety ofFormula I and where structural details have been eliminated for clarity.

[0064] In Scheme I, a vinyl azlactone is first treated with afree-radical initiator to form the transient azlactone radical shown.This radical may be captured by an organonitroxide of the formulaON(R²)₂ (previously described), or may oligomerize with additional vinylazlactone to produce an oligomeric radical having a plurality of pendantazlactone groups. This oligomeric radical may then be captured by theorganonitroxide to form an oligomeric initiator of Formula I, where(with reference to Formula I) X is the residue of a free radicalinitiator, m is 1 to 20, and q for the (CH₂)_(q) adjacent to the X groupis 1. The degree of oligomerization depends on the substitution of theolefinic bond. With reference to formula I, those compounds where R¹ isH oligomerize readily, however where R¹ is an alkyl group, the compoundsoligomerize less readily. As in any conventional oligomerizationprocess, the products will comprise a range of molecular weights anddegrees of oligomerization. Thus the value m may be a non-integralvalue, reflecting the average degree of oligomerization of the product.

[0065] Any conventional free radical initiator, including photo- andthermal initiators may be used to generate the initial azlactoneradical. The degree of oligomerization can be controlled by the amountof initiator, the temperature and concentration. In one embodiment, theinitiator is a photoinitiator and is capable of being activated by UVradiation, e.g., at wavelengths from about 250 mm to about 450 nm, morepreferably at about 351 nm. Useful photoinitiators include e.g., benzoinethers such as benzoin methyl ether and benzoin isopropyl ether,substituted benzoin ethers, substituted acetophenones such as2,2-dimethoxy-2-phenylacetophenone, and substituted alpha-ketols.Examples of commercially available photoinitiators include Irgacure™ 819and Darocur™ 1173 (both available form Ciba-Geigy Corp., Hawthorne,N.Y.), Lucern TPO™ (available from BASF, Parsippany, N.J.) and Irgacure™651, (2,2-dimethoxy-1,2-diphenyl-1-ethanone) which is available fromCiba-Geigy corporation and is.

[0066] Examples of suitable thermal initiators include peroxides such asbenzoyl peroxide, dibenzoyl peroxide, dilauryl peroxide, cyclohexaneperoxide, methyl ethyl ketone peroxide, hydroperoxides, e.g., tert-butylhydroperoxide and cumene hydroperoxide, dicyclohexyl peroxydicarbonate,2,2,-azo-bis(isobutyronitrile), and t-butyl perbenzoate. Examples ofcommercially available thermal initiators include initiators availablefrom DuPont Specialty Chemical (Wilmington, Del.) under the VAZO tradedesignation including VAZO™ 64 (2,2′-azo-bis(isobutyronitrile)) andVAZO™ 52, and Lucidol™ 70 from Elf Atochem North America, Philadelphia,Pa.

[0067] The initiator is used in an amount effective to facilitateoligomerization of the vinyl azlactone and the amount will varydepending upon, e.g., the type of initiator, and the molecular weight ofthe vinyl azlactone. The initiators can be used in amounts from about0.001 part by weight to about 1 parts by weight based on 100 parts vinylazlactone.

[0068] In Scheme II, a halogen-substituted azlactone is treated with adithiocarbamate salt to displace the halide (Hal) to form the depicteddithiocarbamate-substituted azlactone. This may be treated with lightenergy in the presence of an organonitroxide to generate the transientazlactone radical, which is captured by the organonitroxide to produce amonomeric initiator where, with reference to Formula I, q is 0, and X isan H, an alkyl group, a cycloalkyl group, a heterocyclic group, anarenyl group, an aryl group, a nitrile, or an acyl group. Furtherdetails regarding the preparation of azlactones may be found in“Polyazlactones”, Encyclopedia of Polymer Science and Engineering, vol.11, 2^(nd) Ed., John Wiley and Sons, pp. 558-571 (1988). Alternatively,the depicted halide compound may be converted to the indicatedorganonitroxide by ATRP methods.

[0069] Useful azlactone initiators include the following compounds:

[0070] Ring-opened azlactone compounds of Formula II may be made bynucleophilic addition of a compound of the formula R⁵(ZH)_(p) to theazlactone carbonyl of Formula I as shown below. In the Scheme III below,R⁵ is an inorganic or organic group of valence p, having one or aplurality of nucleophilic -ZH groups that are capable of reacting withthe azlactone moiety of Formula I. R⁵(ZH)_(p) may be water. R¹, R³ toR⁵, ON(R²)₂, X, Q, Z, n, q and p are as defined in Formulas I and II.For simplicity, the repeat unit of the oligomerized initiators is notshown.

[0071] If organic, R⁵ may be a polymeric or non-polymeric organic groupthat has a valence of p and is the residue of a nucleophilicgroup-substituted compound, R⁵(ZH)_(p), in which Z is —O—, —S—, or —NRwherein R⁶ can be a H, an alkyl, a cycloalkyl or aryl, a heterocyclicgroup, an arenyl and p is at least one, preferably at least 2. Theorganic moiety R⁵ has a molecular weight up to 20,000, preferablyselected from mono- and polyvalent hydrocarbyl (i.e., aliphatic and arylcompounds having 1 to 30 carbon atoms and optionally zero to fourcatenary heteroatoms of oxygen, nitrogen or sulfur), polyolefin,polyoxyalkylene, polyester, polyolefin, polyacrylate, or polysiloxanebackbones. If inorganic, R⁵ may comprise metal- or nonmetal oxides suchas silica, alumina or glass having one or a plurality of -ZH groups onthe surface.

[0072] In one embodiment, R⁵ comprises a non-polymeric aliphatic,cycloaliphatic, aromatic or alkyl-substituted aromatic moiety havingfrom 1 to 30 carbon atoms. In another embodiment, R⁵ comprises apolyoxyalkylene, polyester, polyolefin, polyacrylate, or polysiloxanepolymer having pendent or terminal reactive -ZH groups. Useful polymersinclude, for example, hydroxyl, thiol or amino terminated polyethylenesor polypropylenes, hydroxyl, thiol or amino terminated poly(alkyleneoxides) and polyacylates having pendant reactive functional groups, suchas hydroxyethyl acrylate polymers and copolymers.

[0073] Depending on the nature of the functional group(s) of R⁵(ZH)_(p),a catalyst may be added to effect the condensation reaction. Normally,primary amine groups do not require catalysts to achieve an effectiverate of condensation with the azlactone group of Formula I. Acidcatalysts such as trifluoroacetic, ethanesulfonic, and toluenesulfonicacids are effective catalysts with hydroxyl groups and secondary amines.

[0074] With respect to the compound R⁵(ZH)_(p), p is at least one, butpreferably p is at least two. The multiple -ZH groups of thepolyfunctional compound may be the same or different. Multifunctionalcompounds may be reacted with the azlactone compound of Formula I toproduce polyfunctional initiators of Formula II, where p is at leasttwo. Such polyfunctional initiators allow the preparation of graft, andstar (co)polymers and other useful topologies.

[0075] Useful alcohols of the formula R⁵(ZH)_(p) include aliphatic andaromatic monoalcohols and polyols. Useful monoalcohols include methanol,ethanol, octanol, decanol, and phenol. The polyols useful in the presentinvention include aliphatic or aromatic polyols having 1 to 30 carbonatoms, at least two hydroxyl groups. Example of useful polyols includeethylene glycol, propylene glycol, butanediol, 1,3-pentanediol,2,2-oxydiethanol, hexanediol, poly(pentyleneadipate glycol),poly(tetramethylene ether glycol), poly(ethylene glycol),poly(caprolactone diol), poly(1,2-butylene oxide glycol), trimethylolethane, trimethylol propane, trimethylol aminomethane, ethylene glycol,2-butene-1,4-diol, pentaerythritol, dipentaerythritol, andtripentaerythritol. The term “polyol” also includes derivatives of theabove-described polyols such as the reaction product of the polyol withdi- or poly-isocyanate, or di- or poly-carboxylic acid, the molar ratioof polyol to —NCO, or —COOH being 1 to 1.

[0076] Useful amines of the formula R⁵(ZH)_(p) include aliphatic andaromatic monoamines and polyamines. Any primary or secondary amine maybe employed, although primary amines are preferred to secondary amines.Useful monoamines include, for example, methyl-ethyl-, propyl-, hexyl-,octyl, dodecyl-, dimethyl-, and aniline. The term “di-, or polyamine,”refers to organic compounds containing at least two non-tertiary aminegroups. Aliphatic, aromatic, cycloaliphatic, and oligomeric di- andpolyamines all are considered useful in the practice of the invention.Representative of the classes of useful di- or polyamines are4,4′-methylene dianiline,3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro[5,5]undecane, andpolyoxyethylenediamine. Many di- and polyamines, such as those justnamed, are available commercially, for example, those available fromHuntsman Chemical, Houston, Tex. Preferred di- or polyamines includealiphatic diamines or aliphatic di- or polyamines and more specificallycompounds with two primary amino groups, such as ethylene diamine,hexamethylene diamine, dodecanediamine, and the like.

[0077] Useful thiols of the formula R⁵(ZH)_(p) include aliphatic andaromatic monothiols and polythiols Useful alkyl thiols include methyl,ethyl and butyl thiol, as well as 2-mercaptoethanol,3-mercapto-1,2-propanediol, 4-mercaptobutanol, mercaptoundecanol,2-mercaptoethylamine, 2,3-dimercaptopropanol,3-mercaptopropyltrimethoxysilane, 2-chloroethanethiol,2-amino-3-mercaptopropionic acid, dodecyl mercaptan, thiophenol,2-mercaptoethyl ether, and pentaerythritol tetrathioglycolate. Usefulsoluble, high molecular weight thiols include polyethylene glycoldi(2-mercaptoacetate), LP-3^(tm) resins supplied by Morton Thiokol Inc.(Trenton, N.J.), and Permapol P3 ^(tm) resins supplied by ProductsResearch & Chemical Corp. (Glendale, Calif.) and compounds such as theadduct of 2-mercaptoethylamine and caprolactam.

[0078] The invention provides multifunctional initiators as shown inScheme III, whereby an azlactone initiator of Formula I is ring-openedby a multireactive or multifunctional compound of the formulaR⁵(ZH)_(p), where p is at least 2. Such multifunctional initiators maybe used to produce branched, star and graft (co)polymers and othertopologies. It will also be apparent that such (co)polymers may also beprepared by first polymerizing a monomer using the initiator of FormulaI, to produce polymers having an azlactone group at one terminal end,and then subsequently reacting the polymers with a polyfunctionalcompound of the formula R⁵(ZH)_(p), where p is at least 2.

[0079] Although the repeat unit of the oligomeric initiators is notshown in Scheme III, it will be appreciated that the -ZH groups of amultifunctional compound R⁵(ZH)_(p) may react with the multiple, pendentazlactone groups on the same oligomer, or the azlactone groups ondifferent oligomers to form a crosslinked composition. Additionally itwill be appreciated that the multiple R⁵ groups depicted in Formula IImay be the same R⁵ group whose multiple ZH groups react with adjacentazlactone groups on the same oligomer.

[0080] In another embodiment, the multifunctional initiators maycomprise a solid support having a plurality of initiator moieties on thesurface thereof. Such initiator-functionalized supports have the generalstructure (corresponding to Formula II):

[0081] wherein X, R¹, ON(R²)₂, R³, R⁴, X, Z, q, p and n are aspreviously described for Formula II and SS is a solid supportcorresponding to R⁵. For clarity, the repeat unit of the oligomericinitiator is not shown in Formula IV. The solid support materialincludes functional groups to which initiator molecules of Formula I canbe covalently attached for effecting polymerization on the solidsurface. Useful functional groups include hydroxyl, amino and thiolfunctional groups corresponding to -ZH.

[0082] The solid support material (SS) can be organic or inorganic. Itcan be in the form of a solid, gel, glass, etc. It can be in the form ofa plurality of particles (e.g., beads, pellets, or microspheres),fibers, a membrane (e.g., sheet or film), a disc, a ring, a tube, or arod, for example. Preferably, it is in the form of a plurality ofparticles or a membrane. It can be swellable or non-swellable and porousor nonporous.

[0083] The support material (SS) can be a polymeric material that can beused in conventional solid phase synthesis. It is chosen such that it isgenerally insoluble in the solvents or other components used insynthetic reactions that occur during the course of solid phasesynthesis. Examples of useable pre-existing support materials aredescribed in G. B. Fields et al., Int. J. Peptide Protein Res., 35, 161(1990) and G. B. Fields et al., in Synthetic Peptides: A User's Guide,G. A. Grant, Ed., pages 77-183, W.H. Freeman and Co., New York, N.Y.(1992). The support material is in the form of an organic polymericmaterial, such as polystyrenes, polyalkylenes, nylons, polysulfones,polyacrylates, polycarbonates, polyesters, polyimides, polyurethanes,etc. and having hydroxyl, amino or thiol substituents on the surface.For pre-existing support materials, a preferred support material ispolystyrene.

[0084] The initiators may be used for controlled radical polymerizationof ethylenically unsaturated monomers. Examples of ethylenicallyunsaturated monomers that may be polymerized include (meth)acrylatessuch as ethyl(meth)acrylate, propyl(meth)acrylate, butyl(meth)acrylate,isooctyl(meth)acrylate and other alkyl(meth)acrylates; alsofunctionalized (meth)acrylates including glycidyl(meth)acrylate,trimethoxysilyl propyl (meth)acrylate, allyl(meth)acrylate,hydroxyethyl(meth)acrylate, hydroxypropyl (meth)acrylate,dialkylaminoalkyl(meth)acrylates; fluoroalkyl(meth)acrylates;(meth)acrylic acid, fumaric acid (and esters), itaconic acid (andesters), maleic anhydride; styrene, α-methyl styrene; vinyl halides suchas vinyl chloride and vinyl fluoride; (meth)acrylonitrile; vinylidenehalides; unsaturated alkylsulphonic acids or derivatives thereof;2-vinyl-4,4-dimethylazlactone, and (meth)acrylamide or derivativesthereof. Mixtures of such monomers may be used.

[0085] In the present polymerization, the amounts and relativeproportions of initiator is that effective to conduct nitroxide-mediatedradical polymerization (NMP). The concentration and amounts is generallydetermined by the desired molecular weight of the resulting polymer.Accordingly, the amount of initiator can be selected such that theinitiator concentration is from 10⁴ M to 1 M, preferably 10⁻³ to 10⁻¹ M.Alternatively, the initiator can be present in a molar ratio of from10⁻⁴:1 to 10⁻¹:1, preferably from 10⁻³:1 to 5×10⁻²:1, relative tomonomer.

[0086] The present polymerization may be conducted in bulk or in asolvent. Solvents, preferably organic, can be used to assist in thedissolution of the initiator and the polymerizable monomers, and as aprocessing aid. Preferably, such solvents are not reactive with theazlactone group. It may be advantageous to prepare a concentratedsolution of the initiator in a small amount of solvent to simplify thepreparation of the polymerizable composition.

[0087] Suitable solvents include ethers such as diethyl ether, ethylpropyl ether, dipropyl ether, methyl t-butyl ether, di-t-butyl ether,glyme (dimethoxyethane), diethylene glycol dimethyl ether; cyclic etherssuch as tetrahydrofuran and dioxane; alkanes; cycloalkanes; aromatichydrocarbon solvents such as benzene, toluene, o-xylene, m-xylene,p-xylene; halogenated hydrocarbon solvents; acetonitrile; lactones suchas butyrolactone, and valerolactones; ketones such as acetone, methylethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone;sulfones such as tetramethylene sulfone, 3-methylsulfolane,2,4-dimethylsulfolane, butadiene sulfone, methyl sulfone, ethyl sulfone,propyl sulfone, butyl sulfone, methyl vinyl sulfone,2-(methylsulfonyl)ethanol, and 2,2′-sulfonyldiethanol; amides such asdimethyl formamide; sulfoxides such as dimethyl sulfoxide; cycliccarbonates such as propylene carbonate, ethylene carbonate and vinylenecarbonate; carboxylic acid esters such as ethyl acetate, MethylCellosolve™ and methyl formate; and other solvents such as methylenechloride, nitromethane, acetonitrile, and glycol sulfite, mixtures ofsuch solvents, and supercritical solvents (such as CO₂). The presentpolymerization may also be conducted in accordance with knownsuspension, emulsion and precipitation polymerization processes.

[0088] The polymerization reaction may be controlled by matching thereactivity of the nitroxide groups in the initiator with the monomer,and by matching the energetics of bond breaking and bond forming indormant species, e.g., dormant polymer chains and transition metalspecies. Matching the reactivities of the initiator with the monomerdepends to some degree on the radical stabilizing effects of thesubstituents. Such matching of substituents on the initiator and monomertypically provides a beneficial balance of the relative reactivities ofthe initiator and monomer.

[0089] Polymerizing may be conducted at a temperature of from 20 to 200°C., preferably from 100 to 160° C. and most preferably from 100 to 140°C., although the temperature is dependent on the reactivity of thespecific organonitroxide used. The reaction should be conducted for alength of time sufficient to convert at least 10% (preferably at least50%, more preferably at least 75% and most preferably at least 90%) ofthe monomer to polymer. Typically, the reaction time will be fromseveral minutes to 5 days, preferably from 30 minutes to 3 days, andmost preferably from 1 to 24 hours.

[0090] Polymerizing may be conducted at a pressure of from 0.1 to 100atmospheres, preferably from 1 to 50 atmospheres and most preferably atambient pressure (although the pressure may not be measurable directlyif conducted in a sealed vessel). An inert gas such as nitrogen or argonmay be used.

[0091] If desired, a “one-pot” synthesis may be used whereby theazlactone initiator is prepared according either Scheme I or II, andthen the monomer(s) is added. Typically, the initiator is generated at afirst temperature that is lower than that required to effectpolymerization of the monomer(s), then the temperature is raised. Thus,the initiator is prepared at a temperature ranging from 20 to 100° C.,the monomer(s) added, and the temperature raised to 100 to 200° C.Further, the initiator may also be prepared in the presence ofmonomer(s) at a first temperature that is sufficient to effect thepreparation of the initiator, but too low to effect polymerization ofthe monomer(s), and then the temperature is raised to effectpolymerization of the monomer(s).

[0092] If desired, a conventional free-radical initiator may be added asan accelerant to the polymerizable mixture.

[0093] The (co)polymers obtained by the method of the invention may bedescribed as telechelic (co)polymers comprising polymerized units of oneor more free radically (co)polymerizable monomers (as previouslydescribed), a first terminal group selected from the group derived fromON(R²)₂ and a second azlactone terminal group derived from the initiatorof Formulas I or II:

[0094] Such (co)polymers have the general formula

Az-(M¹)_(x)(M²)_(x)(M³)_(x) . . . (M^(Ω))_(x)—ON(R²)₂,

[0095] wherein “—ON(R²)₂ is derived from the organonitroxide moiety,

[0096] M¹ to M^(Ω) are each polymerized monomer units derived from aradically (co)polymerizable monomer unit having an average degree ofpolymerization x,

[0097] each x is independent, and

[0098] Az is an azlactone group or a ring-opened aziactone group.

[0099] The polymer product retains the functional group “ON(R²)₂” at afirst terminal end of the polymer to initiate a further polymerizationor may be used for further functionalization. The polymer productfurther comprises either the azlactone moiety or the ring-openedazlactone moiety of the initiator at a second terminal end, which may befurther reacted or functionalized as desired. Because the two terminalmoieties have different functionality and reactivity, each terminus maybe independently functionalized.

[0100] Where an initiator of Formula I is used, the second terminalgroup “Az” will comprise the residue of the azlactone group of theformula:

[0101] where R¹, R³, R⁴, Q, X, n, q and m are as previously defined forFormula I.

[0102] Alternatively, when using the initiators of Formula II, thesecond terminal group “Az” will comprise the ring-opened residue of theazlactone group:

[0103] where R¹, R³, R⁴, R⁵, Z, Q, X, n, q and m are as previouslydefined for Formula II. Again, the R⁵ groups depicted for Formula VI maybe derived from the same molecule or different molecules of R⁵(ZH)_(p).

[0104] The terminal “—ON(R²)₂” group may be functionalized independentlyfrom the terminal “Az” group. For example, where R² contains a reactivegroup such as a hydroxyl group, the reactive group may be reacted withan electrophile such as a carboxylic acid, carboxylic anhydride, orcarboxylic acid chloride to produce a carboxylic ester. Additionalmethods of converting an alkoxyamine group to other functional groupsare known in the art, and reference may be made to Macromol., vol. 34,pp 3856-3862, 2001.

[0105] The present invention encompasses a novel process for preparingrandom, block, multi-block, star, gradient, random hyperbranched anddendritic copolymers, as well as graft or “comb” copolymers. Each ofthese different types of copolymers will be described hereunder.

[0106] Since NMP is a “living” or “controlled” polymerization, it may beinitiated and terminated as desired. Thus, in one embodiment, once thefirst monomer is consumed in the initial polymerizing step, a secondmonomer may then be added to form a second block on the growing polymerchain in a second polymerizing step. Additional polymerizations with thesame or different monomer(s) may be performed to prepare multi-blockcopolymers. The subsequent polymer steps may use the same initiatorsystem as in the first step of the polymerization, or another may bechosen to reflect or “match” the different reactivity of the subsequentmonomers.

[0107] Because NMP is radical polymerization, blocks may be prepared inessentially any order. One is not necessarily limited to preparing blockcopolymers where the sequential polymerizing steps must flow from theleast stabilized polymer intermediate to the most stabilized polymerintermediate, such as is necessary in ionic polymerization. Thus, onemay prepare a multi-block copolymer in which a polyacrylonitrile or apoly(meth)acrylate block is prepared first, then a styrene or butadieneblock is attached thereto, etc.

[0108] Furthermore, a linking group is not necessary to join thedifferent blocks of the present block copolymer. One may simply addsuccessive monomers to form successive blocks. Further, it is alsopossible (and in some cases advantageous) to first isolate a (co)polymerproduced by the present NMP process, then react the polymer with anadditional monomer using a different initiator/catalyst system (to“match” the reactivity of the growing polymer chain with the newmonomer). In such a case, the product polymer having a terminal“ON(R²)₂” group acts as the new initiator for the further polymerizationof the additional monomer. Since the novel initiators provide a reactivegroup “Az” at a terminal end of the polymer, linking groups may be usedto join two polymer blocks. For example, in one embodiment, a polymerprepared in accord with the present invention, and having an azlactonegroup of Formula V at one terminus, may be reacted with a second polymerblock having a nucleophilic terminal group.

[0109] Statistical copolymers may be produced using the initiators ofthe present invention. Such copolymers may use 2 or more monomers in arange of about 0-100% by weight of each of the monomers used. Theproduct copolymer will be a function of the molar amounts of themonomers used and the relative reactivity of the monomers.

[0110] The present invention also provides graft or “comb” copolymers.Here, a first (co)polymer having pendent nucleophilic functional groups,such hydroxy-, amino- or thio-groups, etc. is provided. An example of auseful (co)polymers include hydroxyethyl acrylate (co)polymers. Next,the reactive functional groups of the first (co)polymer is reacted withthe azlactone initiators of Formula I to provide a (co)polymer havingpendent, ring-opened initiator moieties, the reaction product having thestructure of Formula II, where R⁵ is the residue of the first(co)polymer. This product (co)polymer may then be used as an initiatorto polymerize the previously-described monomers to produce a comb(co)polymer. Alternatively, the first (co)polymer may be reacted with atelechelic (co)polymer of the invention, whereby the reactive “Az”terminal group reacts with the pendent reactive group of the first(co)polymer.

[0111] Gradient or tapered copolymers can be produced using NMP bycontrolling the proportion of two or more monomers being added. Forexample, one can prepare a first block or an oligomer of a firstmonomer, then a mixture of the first monomer and a second distinctmonomer can be added in proportions of from, for example, 1:1 to 9:1 offirst monomer to second monomer. After conversion of all monomer(s) iscomplete, sequential additions of first monomer-second monomers mixturescan provide subsequent “blocks” in which the proportions of firstmonomer to second monomer vary. Thus, the invention provides copolymersobtained from two or more radically (co)polymerizable monomers whereinthe copolymer has a composition that varies along the length of thepolymer chain from azlactone terminus to opposite terminus based on therelative reactivity ratios of the monomers and instantaneousconcentrations of the monomers during polymerization

EXAMPLES

[0112] All reagents unless otherwise noted were purchased from Aldrich(Milwaukee, Wis.) and were used in their delivered condition.Polymerizable reagents were stripped of inhibitors prior to use bypassing them through an alumina column (also supplied by Aldrich).Solvents were purchased from EM Science located in Gibbstown, N.J.

[0113] Glossary VDM 2-vinyl-4,4-dimethyl azlactone TEMPO2,2,6,6-tetramethylpiperidinyloxy monoTEMPO2,2,6,6-Tetramethyl-1-(1-phenyl-ethoxy)-piperidine AzTEMPO4,4-dimethyl-2-[1-(2,2,6,6-tetramethyl-piperidin-1-yloxy)-ethyl]-4H-oxazol-5-one

Preparative Example 1

[0114] Preparation of 2-(2-Bromopropionylamino)-2-methylpropionic acid

[0115] A stirring mixture of 2-aminoisobutyric acid (52.08 g; 0.51 mol),sodium hydroxide (20.20 g; 0.51 mol), water (200 ml) and chloroform (50ml) was cooled to −12° C. 2-Bromopropionyl bromide (100 g; 0.46 mol) inchloroform (150 ml) was added to the mixture over 15 minutes. Thereaction mixture was then allowed to warm to room temperature afterwhich time the mixture was filtered to isolate the solid that hadprecipitated. The solid was combined with hot toluene (700 ml) and thismixture was then allowed to cool. The while solid was isolated byfiltration and was dried under vacuum to afford 77.60 g (70% yield) of2-(2-bromopropionylamino)-2-methylpropionic acid.

Preparative Example 2

[0116] Preparation of2-(2-Diethylthiocarbamoylsulfanylpropionylamino)-2-methylpropionic acid

[0117] To a solution of 2-(2-bromopropionylamino)-2-methylpropionic acid(5.00 g; 0.021 mol) in acetone (100 ml) there was added sodiumdiethylthiocarbamate trihydrate (4.80 g; 0.021 mol). The mixture wasstirred at room temperature for 17 hours after which it was filtered.The filtrate was concentrated under vacuum and the residue was dissolvedin acetone (10 ml). This solution was then filtered and the filtrate wasconcentrated under vacuum to afford 5.00 g (78% yield) of2-(2-diethylthiocarbamoylsulfanylpropionylamino)-2-methylpropionic acidas a yellow solid.

Preparative Example 3

[0118] Preparation of2-Methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]-propionicacid

[0119] A mixture of2-(2-diethylthiocarbamoylsulfanylpropionylamino)-2-methylpropionic acid(4.00 g; 0.0132 mol), TEMPO (2.04 g; 0.0132 mol) and ethyl acetate (35ml) in a glass jar was purged with nitrogen gas for 20 minutes. The jarwas then sealed and the mixture was irradiated with a 350 nm ultravioletlamp (Sylvania 350 Blacklight F15 T8/350 BL available from OsramSylvania, Danvers, Mass.) for 65 hours. The mixture was thenconcentrated under vacuum and diluted with diethyl ether (50 ml). Thesolid was isolated by filtration and was dried under vacuum to afford1.75 g (42% yield) of2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]-propionicacid.

Example 1

[0120] Preparation of4,4-Dimethyl-2-[1-(2,2,6,6-tetramethylpiperidin-1-yloxy)-ethyl]-4H-oxazol-5-one(AzTEMPO).

[0121] To a stirred mixture of2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]-propionicacid (0.50 g; 0.0016 mol), triethylamine (0.16 g; 0.0016 mol) andacetone (5 ml) there was added ethyl chloroformate (0.17 g; 0.0016 mol).After 2 hours, the mixture was filtered and the filtrate wasconcentrated under vacuum. The residue was mixed with hexane (5 ml) andthe solution was decanted from the precipitated solid. The decantedsolution was concentrated under vacuum to give 0.30 g (64% yield) of4,4-dimethyl-2-[1-(2,2,6,6-tetramethylpiperidin-1-yloxy)-ethyl]-4H-oxazol-5-one(AzTEMPO) as a yellow oil.

Example 2

[0122] Preparation of an Azlactone Functional Oligomeric Initiator.

[0123] VDM (1.1 g, 0.0079 mol) and monoTEMPO (0.2 g, 0.0077 mol) weredissolved in toluene (1.3 g) in a three-necked round bottom flaskequipped with magnetic stirring, N₂ inlets and outlets, a condenser anda thermocouple. The mixture was stirred and flushed with nitrogen gasfor a period of 30 minutes after which it was heated to 110° C. with anoil bath for a period of 4 hours.

Example 3

[0124] To the reaction mixture of Example 2 there was added a solutionof styrene (10 g, 0.096 mol) in toluene (10 g) that had beendeoxygenated by bubbling nitrogen gas through it for 30 minutes. Thismixture was stirred at 130° C. for 16 hours after which time is wasanalyzed by gel permeation chromatography. The reaction yielded apolymer with a Mn Of 11,200 and a polydispersity of 1.24. Thetheoretical Mn was 14,400. To qualitatively demonstrate the presence ofthe azlactone groups on the resulting polymer, a tri-functional amine(tris(2-aminoethyl)amine) was added to the polymer. This reactionproduced an insoluble cross-linked polymer, thus demonstrating that thepolystyrene was connected to the oligomeric azlactone initiator and thatthe azlactone groups on the chain-ends were reactive towards mildnucleophiles.

Examples 4-5

[0125] Controlled Polymerization of Styrene using AzTEMPO

[0126] Screw-cap glass vials were charged with styrene and AzTEMPO inamounts as given in the table. Toluene was added in the calculatedamount to give solutions that were 25 wt % solids. The solutions weredeoxygenated by bubbling nitrogen gas through them for 30 minutes. Thevials were then capped and were heated to 130° C. in an oil bath for 16hours, after which time the vials were opened and the products wereanalyzed by gel permeation chromatography. The results are shown in thetable below. Example 4 Example 5 Styrene  0.997 g (0.0096 mol)  1.019 g(0.0098 mol) AzTEMPO  0.026 g (0.000088 mol) 0.0047 g (0.000018 mol)Calculated Mn 11350 g/mol  64250 g/mol (100% conversion) Actual Mn  2790g/mol  23900 g/mol PDI  1.76  2.05 Monomer converted 43% 62%

Example 6

[0127] Preparation ofN-{2-[Bis-(2-{2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]-propionylamino}-ethyl)-amino]-ethyl}-2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]propionamide.

[0128] A solution of tris(2-aminoethyl)amine (0.032 g; 0.00022 mol) intetrahydrofuran (2.0 ml) was combined with AzTEMPO (0.20 g; 0.00067 mol)and the solution was stirred at room temperature for 30 minutes. Thesolution was concentrated under vacuum to give a residue that wastriturated with hexane and filtered. The resultant white powder wasdried under vacuum to give 0.12 g (51% yield) of product.

Example 7

[0129] Polymerization of styrene usingN-{2-[bis-(2-{2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]-propionylamino}-ethyl)-amino]-ethyl}-2-methyl-2-[2-(2,2,6,6-tetramethylpiperidin-1-yloxy)-propionylamino]propionamide.

[0130] A three-arm star polymer of styrene was prepared using theinitiator of Example 6. A 30 weight percent solution of the initiator intoluene (0.0253 g; 0.000024 mol of initiator) was mixed with styrene.The solution was deoxygenated by bubbling nitrogen gas through it for 30minutes and was then heated to 130° C. After 24 hours the solution wasallowed to cool to room temperature and the polymer was precipitatedfrom the solution by the addition of methanol. The polymer was analyzedby gel permeation chromatography and was found to have Mn of 16,256g/mol and a PDI of 1.18. It was determined gravimetrically that 40% ofthe monomer was converted in the reaction.

Example 8

[0131] A three-arm star polymer of styrene was prepared by reaction of alinear styrene polymer with a trifunctional amine. AzTEMPO (0.196 g;0.00066 mol) and styrene (13.696 g; 0.132 mol) were mixed in toluene(13.9 g). The solution was deoxygenated by bubbling nitrogen gas throughit for 30 minutes and was then heated to 130° C. After 16 hours thesolution was allowed to cool to room temperature and the resultantpolymer was analyzed by gel permeation chromatography. The numberaverage molecular weight was found to be 20,611 g/mol. As the solutionwas stirred, a 1 wt % solution of tris(2-aminoethyl)amine (0.033 g;0.000226 mol) in toluene was added in two portions. The product wasanalyzed by gel permeation chromatography after the addition of eachportion of the amine. After the addition of the first portion, thethree-arm polymer that formed was found to have Mn of 50,061 g/mol andthe relative amount of this polymer product increased after the additionof the second portion of amine.

We claim:
 1. A telechelic (co)polymer comprising polymerized units ofone or more free radically (co)polymerizable monomers, an firstring-opened azlactone terminal group; and a second terminal group thatis the residue of an organonitroxide.
 2. The (co)polymer of claim 1having a molecular weight distribution of less than 2.0.
 3. Thecopolymer of claim 1 comprising two or more blocks of units obtainedfrom free radically (co)polymerizable monomers, wherein the blockcopolymer has an azlactone residue at a first terminal end and, and theresidue of an organonitroxide at the second terminal end.
 4. The(co)polymer of claim 1 comprising polymerized units obtained from two ormore radically (co)polymerizable monomers wherein the copolymer has acomposition that varies along the length of the polymer chain fromazlactone terminus to opposite terminus based on the relative reactivityratios of the monomers and instantaneous concentrations of the monomersduring polymerization.
 5. The (co)polymer of claim 1, wherein said(co)polymer comprises polymerized monomer units selected from the groupconsisting of (meth)acrylic acid and esters thereof; fumaric acid andesters thereof; itaconic acid and esters thereof; maleic anhydride;styrene; α-methyl styrene; vinyl halides; (meth)acrylonitrile,vinylidene halides; butadienes; unsaturated alkylsulphonic acids andesters and halides thereof; and (meth)acrylamides, and mixtures thereof;said (co)polymer having an azlactone residue at a first terminal end ofthe (co)polymer chain and a residue of an organonitroxide at a secondterminal end of the (co)polymer chain.
 6. The (co)polymer of claim 1having the structure Az-(M¹)_(x)—ON(R²)₂, wherein ON(R²)₂ is the residueof an organonitroxide; M¹ is a monomer unit derived from a radically(co)polymerizable monomer unit having an average degree ofpolymerization x, and Az is a ring-opened azlactone group of theformula:

wherein X is an H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group, an aryl group, a nitrile, an acyl group or theresidue of a free-radical initiator; R¹ is H, an alkyl group, acycloalkyl group, a heterocyclic group, an arenyl group or an arylgroup; R³ and R⁴ are each independently selected from an alkyl, acycloalkyl group, an aryl group, an arenyl group, or R³ and R⁴ takentogether with the carbon to which they are attached form a carbocyclicring; Q is a linking group selected from a covalent bond, (—CH₂—)_(o),—CO—O—(CH₂)₀—, —CO—O—(CH₂CH₂O)_(n)—, —CO—NR⁶—(CH₂)_(o)—,—CO—S—(CH₂)_(o)—, where o is 1 to 12, and R⁶ is is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup; each n is 0 or 1; m is 0 to 20; q is 0 or 1; Z is O, S or NR⁶,wherein R⁶ is H, an alkyl group, a cycloalkyl group, an arenyl group, aheterocyclic group or an aryl group; R⁵ is an organic or inorganicmoiety and has a valency of p.
 7. The (co)polymer of claim 1 having thestructure Az-(M¹)_(x)(M²)_(x)-(M³)_(x) . . . (M^(Ω))_(x)—ON(R²)₂,wherein ON(R²)₂ is the residue of an organonitroxide; M¹ to M^(Ω) areeach polymer blocks of monomer units derived from a radically(co)polymerizable monomer units having an average degree ofpolymerization x, each x is independent, and Az is a ring-openedazlactone group of the formula:

wherein X is an H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group, an aryl group, a nitrile, an acyl group or theresidue of a free-radical initiator; R¹ is H, an alkyl group, acycloalkyl group, a heterocyclic group, an arenyl group or an arylgroup; R³ and R⁴ are each independently selected from an alkyl, acycloalkyl group, an aryl group, an arenyl group, or R³ and R⁴ takentogether with the carbon to which they are attached form a carbocyclicring; Q is a linking group selected from a covalent bond, (—CH₂—)_(o),—CO—O—(CH₂)₀—, —CO—O—(CH₂CH₂O)_(o)—, —CO—NR⁶—(CH₂)_(n)—,—CO—S—(CH₂)_(n)—, where o is 1 to 12, and R⁶ is is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup; each n is 0 or 1; m is 0 to 20; q is 0 or 1; Z is O, S or NR⁶,wherein R is H, an alkyl group, a cycloalkyl group, an arenyl group, aheterocyclic group or an aryl group; R⁵ is an organic or inorganicmoiety and has a valency of p.
 8. The (co)polymer of claim 1 wherein theresidue of the hindered organonitroxide, —ON(R²)₂, is of the formula

wherein R⁷ is an alkyl group, a cycloalkyl group, an arenyl group, aheterocyclic group, an aryl group: R⁸, and R⁹ are independently H, or analkyl group, a cycloalkyl group, an arenyl group, a heterocyclic group,an aryl group, and R⁷ and R⁸, or R⁸ and R⁹, may be taken together toform a carbocyclic ring.
 9. The (co)polymer of claim 1 wherein said R⁵Zgroup is derived from a compound of the formula R⁵(ZH)_(p) wherein R⁵ isan inorganic or organic group of valence p, and -ZH is selected from OH,SH or NHR⁶, wherein R⁶ is H, an alkyl group, a cycloalkyl group, anarenyl group, a heterocyclic group or an aryl group.
 10. The (co)polymerof claim 1, wherein said R⁵ group comprises metal- or nonmetal oxideshaving a plurality of -ZH groups on the surface.
 11. The (co)polymer ofclaim 1, wherein said R⁵ group comprises a non-polymeric aliphatic,cycloaliphatic, aromatic or alkyl-substituted aromatic moiety havingfrom 1 to 30 carbon atoms.
 12. The (co)polymer of claim 1, wherein saidR⁵ group comprises a polyoxyalkylene, polyester, polyolefin,polyacrylate, or polysiloxane polymer having pendent or terminalreactive -ZH groups
 13. A method for preparing the (co)polymer of claim1 comprising addition polymerizing one or more olefinically unsaturatedmonomers using an initiator of the formula:

wherein X is an H, an alkyl group, a cycloalkyl group, a heterocyclicgroup, an arenyl group, an aryl group, a nitrile, an acyl group or theresidue of a free-radical initiator; R¹ is H, an alkyl group, acycloalkyl group, a heterocyclic group, an arenyl group or an arylgroup; ON(R²)₂ is the residue of an organonitroxide; R³ and R⁴ are eachindependently selected from an alkyl, a cycloalkyl group, an aryl group,an arenyl group, or R³ and R⁴ taken together with the carbon to whichthey are attached form a carbocyclic ring; Q is a linking group selectedfrom a covalent bond, (—CH₂—)_(o), —CO—O—(CH₂)_(o)—,CO—O—(CH₂CH₂O)_(o)—, —CO—NR⁶—(CH₂)_(n)—, —CO—S—(CH₂)_(o)—, where o is 1to 12, and R¹ is is H, an alkyl group, a cycloalkyl group, an arenylgroup, a heterocyclic group or an aryl group; each n is 0 or 1; m is 0to 20; q is 0 or 1; Z is O, S or NR⁶, wherein R⁶ is H, an alkyl group, acycloalkyl group, an arenyl group, a heterocyclic group or an arylgroup; R⁵ is an organic or inorganic moiety and has a valency of p. 14.The method of claim 13, wherein m is 0, q is 0, and X is an H, an alkylgroup, a cycloalkyl group, a heterocyclic group, an arenyl group, anaryl group, a nitrile, or an acyl group.
 15. The method of claim 13,wherein m is 1 to 20, X is the residue of a free-radical initiator, andq is
 1. 16. The method of claim 13 wherein R₁ is a C₁ to C₄ alkyl group.17. The method of claim 13 wherein R₁ is H.
 18. The method of claim 13wherein at least one of R₃ and R₄ is a C₁ to C₄ alkyl group.
 19. Themethod of claim 13 wherein R₃ and R⁴ are methyl.
 20. The methodaccording to claim 13, wherein the addition polymerization is conductedat a temperature between 100 to 160° C.
 21. The method according toclaim 13, wherein the olefinically unsaturated monomers are selectedfrom (meth)acrylic acid and esters thereof, fumaric acid and estersthereof, itaconic acid and esters thereof, maleic anhydride; styrene,α-methyl styrene; vinyl halides; (meth)acrylonitrile, vinylidenehalides; vinyl pyridine; unsaturated alkylsulphonic acids and esters andhalides thereof; and (meth)acrylamides, and mixtures thereof.
 22. Themethod according to claim 13, wherein the polymerization is conductedneat or in a solvent.
 23. The method of claim 22 wherein said solvent isselected from ethers, cyclic ethers, alkanes, cycloalkanes, aromatichydrocarbon solvents, halogenated hydrocarbon solvents, acetonitrile,mixtures of such solvents, and supercritical solvents.
 24. The methodaccording to claim 13 further comprising a second polymerizing stepusing one or more additional olefinically unsaturated monomers.
 25. Themethod of claim 13, wherein the initiator is present in a concentrationof from 10⁻⁴ M to 1 M.
 26. The method of claim 13, wherein the molarratio of initiator and monomer(s) is from 10⁴:1 to 10⁻¹:1 of initiatorto monomer(s).